Brontosaurus is a sauropod dinosaur from the Jurassic period of North America. It was originally a different genus from Apatosaurus, but the type species Brontosaurus excelsus was reclassified as a species of Apatosaurus called Apatosaurus excelsus, meaning Brontosaurus was considered scientifically invalid for over 110 years. However, an extensive study published in 2015 by a joint research team of United Kingdom and Portugal concluded that Brontosaurus was a valid genus of sauropod distinct from Apatosaurus, resurrecting the genus.

Wikipedia has a more detailed and comprehensive article on Brontosaurus

Brontosaurus can be created in Jurassic Park: Builder though it requires dino-dollars purchase. Its appearance in the game is odd because when the game was made Brontosaurus was synonymous with Apatosaurus.

Level 11 Brontosaurus

Fully Maxed Brontosaurus

Fully Maxed Brontosaurus in a fight

Inaccurate Apatosaurus synonym evolution fact, which was accurate until 2015.